1. Field of the Invention
The present invention relates to microwave ovens, and more particularly, to a door assembly for a microwave oven, having an improved structure.
2. Background of the Related Art
In general, the microwave oven (MWO) cooks food with intermolecular friction heat generated when molecular array of food is disturbed by a high frequency wave (approx. 2,450 MHz).
FIG. 1 illustrates a perspective view of a related art microwave oven.
Referring to FIG. 1, the related art microwave oven is provided with a body 10, an inner case 20, and an outfit chamber.
The body 10 is provided with a front case 11, an outer case 12, and a frame 13. The inner case 20 is provided inside of the body 10 for holding the food therein. The front case 11 is in a front part of the microwave oven, with a door 14 at one side thereof for opening/closing a front part of the inner case 20. The outer case 12 covers top and side surfaces of the microwave oven, with front edges thereof fastened to the front case 11.
The frame 13 covers a bottom and rear surfaces of the body 10, to protect the inner case 20 and the outfit chamber 30 from an external environment together with the outer case 12 and the front case 11.
In the meantime, the outfit chamber is formed on a side of the inner case 20 for providing various electric components thereto, including a magnetron 31, a high voltage transformer 32, and a fan 33.
The magnetron 31 provides a microwave to an inside of the inner case 20 for heating food. The high voltage transformer 32 provides a high voltage power to the magnetron 31. The fan 33 blows air into an inside of the body 10, for cooling various electric components.
In the meantime, there are brackets 15 fixed to a front surface of the frame 13, and the door 14 rotatably fixed to the brackets 15 opens/closes a front surface of the inner case 20. As described later, when the door 14 is closing, a latch on a door panel 141 pushes a lever on a latch board in the body 10, to operate a switch.
FIG. 2 illustrates a side view of a latch board in a related art microwave oven, and FIG. 3 illustrates a diagram showing operation of an actuator ‘A’ of a switch ‘S’ when the latch 142 of the door is inserted into a latch board 101. The frame 13 is on a front surface of the inner case 20, and the latch board 101 is on the frame 13.
The latch board 101 has three levers L1, L2, and L3, and 3˜5 switches ‘S’ fitted therein. The switches ‘S’ include a first safety switch S1, a second safety switch S2, and a monitor switch S3.
Referring to FIG. 2, the first safety switch ‘S1’ is in a lower part of the latch board 101, the monitor switch ‘S3’ is in a central part, and the second safety switch ‘S2’ in an upper part. Each of the switches ‘S’ is fastened to the latch board 101 with two fastening pins ‘P’ and a hook ‘H’.
There are two holes in a diagonal direction of each of the switches ‘S’. After the fastening pins ‘P’ are aligned with the holes, the switches ‘S’ are pressed down, to insert the switch ‘S’ into the hook ‘H’ and fasten the switch ‘S’.
A related art door latch structure will be described.
Referring to FIG. 2, there are latch inlets 103 in a front part of the latch board 101 for inserting the latch 142. An upper latch inlet 103 has a sloped surface 104 for guiding an upper latch 142a to upward.
Referring to FIG. 3, the upper latch 142a is engaged with one end of the first lever L1 as the upper latch 142a moves up along the sloped surface 104 and drops at an end of the sloped surface 104. In this instance, the upper latch 142a pushes the first lever L1.
In the meantime, a lower latch 142b is inserted into a lower latch inlet 103. In this instance, the lower latch 142b pushes both one end of the second lever L2 and one end of the third lever L3 below the second lever L2.
In this instance, other end of the first lever L1 pushes an actuator A2 of the second safety switch S2, and the second lever L2 and the third lever L3 push the monitor switch S3 and actuators A1 and A3 of the first safety switch S1, respectively.
According to this, the first lever L1 operates the second safety switch S2, the second lever L2 operates the monitor switch S3, and the third lever L3 operates the first safety switch S1.
In the meantime, when the door is opened, a door handle is operated, to lift the latches 142a upward, so that the latches 142 are pulled out of the latch inlets 103. Thereafter, as the levers L, respectively turned by the latches 142, are restored by the springs 107 respectively, the actuators ‘A’ on the switches ‘S’ are released, respectively.
A related art assembly structure of the door will be described. FIG. 4 illustrates fitting of the pin to the related art door, and FIG. 5 illustrates fastening of the pin.
Referring to FIG. 4, there are horizontal members 50 on an upper part and a lower part of an inside of the door 14. The horizontal member 50 is extended form an edge of the door 14. The horizontal member 50 has a pin 55 fastened thereto for serving as a rotation shaft of the door 14.
Referring to FIG. 5, the horizontal member 50 has a hole 51 formed therein, for inserting the pin 55 therein. The pin 55 has a flange 56 at a middle part thereof.
According to this, when the pin 55 is inserted into the hole 51 by a predetermined length, the flange 56 is held by a lower surface of the horizontal member 50, when an extension 57 from a rear end of the pin 55 is projected by a length beyond the horizontal member 50. The extension 57 is flattened by caulking.
Thus, as the horizontal member 50 is clamped between the flange 56 and the extension 57, the pin 55 is fastened to one side of the horizontal member 50.
In the meantime, as shown in FIG. 1, the brackets 15 are on one side of the frame 13. The bracket 15 has a hole 15a in one end part thereof, to which the pin 55 is inserted. Thus, the door 14 is rotatably mounted on the frame 13. The pin 55 serves as a rotation shaft of the door.
As described, the related art door latch board has the following problems.
First, the many levers and springs required as many as a number of switches increase a number of components, and results in a complicated assembly process.
Second, the holes, fastening pins, and hooks required for fastening the switches to the latch board requires complicated switching fastening process.
Third, since the pin fitted to the door is a separate component, a fitting process increases, and the extension of the pin is damaged in the caulking.